Ulcerative colitis is a type of inflammatory bowel disease in which the inner lining of the large intestine (colon) and rectum become inflamed. Inflammation usually begins in the rectum and lower large intestine and spreads upward, potentially involving the entire colon. Ulcerative colitis causes diarrhea and frequent emptying of the colon. As cells on the surface of the colon die and fall off, ulcers (open sores) form, leading to pus, mucus, and bleeding.
Ulcerative colitis may occur at any age but is most common in older children and young adults and may run in some families. Although there is no cure, the right treatment plan can minimize or eliminate ulcerative colitis symptoms with medication, lifestyle changes, and, in some cases, surgery. The condition also can go into periods of remission.